Building Your First Cross-Chain USDC Sending and Receiving Application

This tutorial contains a solidity contract that can be deployed onto any CCTP-supported chain to form a fully functioning cross-chain application with the ability for users to request, from one contract, that USDC is sent to an address on a different chain.

Summary

Included in this repository is:

• Example Solidity Code
• Example Forge local testing setup
• Testnet Deploy Scripts
• Example Testnet testing setup

Environment Setup

• Node 16.14.1 or later, npm 8.5.0 or later: https://docs.npmjs.com/downloading-and-installing-node-js-and-npm
• forge 0.2.0 or later: https://book.getfoundry.sh/getting-started/installation

Testing Locally

Clone down the repo, cd into it, then build and run unit tests:

git clone https://github.com/wormhole-foundation/hello-usdc.git
cd hello-usdc
npm run build
forge test --via-ir

Expected output is

Running 1 test for test/HelloUSDC.t.sol:HelloUSDCTest
[PASS] testCrossChainDeposit() (gas: 1338038)
Test result: ok. 1 passed; 0 failed; finished in 5.64s

Deploying to Testnet

You will need a wallet with some testnet ETH and testnet USDC (eth).

EVM_PRIVATE_KEY=your_wallet_private_key npm run deploy

Testing on Testnet

You will need a wallet with testnet ETH.

You must have also deployed contracts onto testnet (as described in the above section).

To test sending and receiving a message on testnet, execute the test as such:

EVM_PRIVATE_KEY=your_wallet_private_key npm run test